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llvm-project/clang/lib/CodeGen/CGExpr.cpp

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//===--- CGExpr.cpp - Emit LLVM Code from Expressions ---------------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Expr nodes as LLVM code.
//
//===----------------------------------------------------------------------===//
#include "CodeGenFunction.h"
#include "CodeGenModule.h"
#include "clang/AST/AST.h"
#include "clang/Basic/TargetInfo.h"
#include "llvm/Constants.h"
#include "llvm/DerivedTypes.h"
#include "llvm/Function.h"
#include "llvm/GlobalVariable.h"
#include "llvm/Support/MathExtras.h"
#include "llvm/Target/TargetData.h"
using namespace clang;
using namespace CodeGen;
//===--------------------------------------------------------------------===//
// Miscellaneous Helper Methods
//===--------------------------------------------------------------------===//
/// CreateTempAlloca - This creates a alloca and inserts it into the entry
/// block.
llvm::AllocaInst *CodeGenFunction::CreateTempAlloca(const llvm::Type *Ty,
const char *Name) {
return new llvm::AllocaInst(Ty, 0, Name, AllocaInsertPt);
}
/// EvaluateExprAsBool - Perform the usual unary conversions on the specified
/// expression and compare the result against zero, returning an Int1Ty value.
llvm::Value *CodeGenFunction::EvaluateExprAsBool(const Expr *E) {
QualType BoolTy = getContext().BoolTy;
if (!E->getType()->isAnyComplexType())
return EmitScalarConversion(EmitScalarExpr(E), E->getType(), BoolTy);
return EmitComplexToScalarConversion(EmitComplexExpr(E), E->getType(),BoolTy);
}
/// EmitAnyExpr - Emit code to compute the specified expression which can have
/// any type. The result is returned as an RValue struct. If this is an
/// aggregate expression, the aggloc/agglocvolatile arguments indicate where
/// the result should be returned.
RValue CodeGenFunction::EmitAnyExpr(const Expr *E, llvm::Value *AggLoc,
bool isAggLocVolatile) {
if (!hasAggregateLLVMType(E->getType()))
return RValue::get(EmitScalarExpr(E));
else if (E->getType()->isAnyComplexType())
return RValue::getComplex(EmitComplexExpr(E));
EmitAggExpr(E, AggLoc, isAggLocVolatile);
return RValue::getAggregate(AggLoc);
}
/// getAccessedFieldNo - Given an encoded value and a result number, return
/// the input field number being accessed.
unsigned CodeGenFunction::getAccessedFieldNo(unsigned Idx,
const llvm::Constant *Elts) {
if (isa<llvm::ConstantAggregateZero>(Elts))
return 0;
return cast<llvm::ConstantInt>(Elts->getOperand(Idx))->getZExtValue();
}
//===----------------------------------------------------------------------===//
// LValue Expression Emission
//===----------------------------------------------------------------------===//
/// EmitLValue - Emit code to compute a designator that specifies the location
/// of the expression.
///
/// This can return one of two things: a simple address or a bitfield
/// reference. In either case, the LLVM Value* in the LValue structure is
/// guaranteed to be an LLVM pointer type.
///
/// If this returns a bitfield reference, nothing about the pointee type of
/// the LLVM value is known: For example, it may not be a pointer to an
/// integer.
///
/// If this returns a normal address, and if the lvalue's C type is fixed
/// size, this method guarantees that the returned pointer type will point to
/// an LLVM type of the same size of the lvalue's type. If the lvalue has a
/// variable length type, this is not possible.
///
LValue CodeGenFunction::EmitLValue(const Expr *E) {
switch (E->getStmtClass()) {
default: {
printf("Statement class: %d\n", E->getStmtClass());
WarnUnsupported(E, "l-value expression");
llvm::Type *Ty = llvm::PointerType::getUnqual(ConvertType(E->getType()));
return LValue::MakeAddr(llvm::UndefValue::get(Ty),
E->getType().getCVRQualifiers());
}
case Expr::CallExprClass: return EmitCallExprLValue(cast<CallExpr>(E));
case Expr::DeclRefExprClass: return EmitDeclRefLValue(cast<DeclRefExpr>(E));
case Expr::ParenExprClass:return EmitLValue(cast<ParenExpr>(E)->getSubExpr());
case Expr::PredefinedExprClass:
return EmitPredefinedLValue(cast<PredefinedExpr>(E));
case Expr::StringLiteralClass:
return EmitStringLiteralLValue(cast<StringLiteral>(E));
case Expr::ObjCIvarRefExprClass:
return EmitObjCIvarRefLValue(cast<ObjCIvarRefExpr>(E));
case Expr::UnaryOperatorClass:
return EmitUnaryOpLValue(cast<UnaryOperator>(E));
case Expr::ArraySubscriptExprClass:
return EmitArraySubscriptExpr(cast<ArraySubscriptExpr>(E));
case Expr::ExtVectorElementExprClass:
return EmitExtVectorElementExpr(cast<ExtVectorElementExpr>(E));
case Expr::MemberExprClass: return EmitMemberExpr(cast<MemberExpr>(E));
case Expr::CompoundLiteralExprClass:
return EmitCompoundLiteralLValue(cast<CompoundLiteralExpr>(E));
}
}
/// EmitLoadOfLValue - Given an expression that represents a value lvalue,
/// this method emits the address of the lvalue, then loads the result as an
/// rvalue, returning the rvalue.
RValue CodeGenFunction::EmitLoadOfLValue(LValue LV, QualType ExprType) {
if (LV.isSimple()) {
llvm::Value *Ptr = LV.getAddress();
const llvm::Type *EltTy =
cast<llvm::PointerType>(Ptr->getType())->getElementType();
// Simple scalar l-value.
if (EltTy->isSingleValueType()) {
llvm::Value *V = Builder.CreateLoad(Ptr, LV.isVolatileQualified(),"tmp");
// Bool can have different representation in memory than in registers.
if (ExprType->isBooleanType()) {
if (V->getType() != llvm::Type::Int1Ty)
V = Builder.CreateTrunc(V, llvm::Type::Int1Ty, "tobool");
}
return RValue::get(V);
}
assert(ExprType->isFunctionType() && "Unknown scalar value");
return RValue::get(Ptr);
}
if (LV.isVectorElt()) {
llvm::Value *Vec = Builder.CreateLoad(LV.getVectorAddr(),
LV.isVolatileQualified(), "tmp");
return RValue::get(Builder.CreateExtractElement(Vec, LV.getVectorIdx(),
"vecext"));
}
// If this is a reference to a subset of the elements of a vector, either
// shuffle the input or extract/insert them as appropriate.
if (LV.isExtVectorElt())
return EmitLoadOfExtVectorElementLValue(LV, ExprType);
if (LV.isBitfield())
return EmitLoadOfBitfieldLValue(LV, ExprType);
assert(0 && "Unknown LValue type!");
//an invalid RValue, but the assert will
//ensure that this point is never reached
return RValue();
}
RValue CodeGenFunction::EmitLoadOfBitfieldLValue(LValue LV,
QualType ExprType) {
unsigned StartBit = LV.getBitfieldStartBit();
unsigned BitfieldSize = LV.getBitfieldSize();
llvm::Value *Ptr = LV.getBitfieldAddr();
const llvm::Type *EltTy =
cast<llvm::PointerType>(Ptr->getType())->getElementType();
unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
// In some cases the bitfield may straddle two memory locations.
// Currently we load the entire bitfield, then do the magic to
// sign-extend it if necessary. This results in somewhat more code
// than necessary for the common case (one load), since two shifts
// accomplish both the masking and sign extension.
unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
llvm::Value *Val = Builder.CreateLoad(Ptr, LV.isVolatileQualified(), "tmp");
// Shift to proper location.
Val = Builder.CreateLShr(Val, llvm::ConstantInt::get(EltTy, StartBit),
"bf.lo");
// Mask off unused bits.
llvm::Constant *LowMask =
llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, LowBits));
Val = Builder.CreateAnd(Val, LowMask, "bf.lo.cleared");
// Fetch the high bits if necessary.
if (LowBits < BitfieldSize) {
unsigned HighBits = BitfieldSize - LowBits;
llvm::Value *HighPtr =
Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
"bf.ptr.hi");
llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
LV.isVolatileQualified(),
"tmp");
// Mask off unused bits.
llvm::Constant *HighMask =
llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, HighBits));
HighVal = Builder.CreateAnd(HighVal, HighMask, "bf.lo.cleared");
// Shift to proper location and or in to bitfield value.
HighVal = Builder.CreateShl(HighVal,
llvm::ConstantInt::get(EltTy, LowBits));
Val = Builder.CreateOr(Val, HighVal, "bf.val");
}
// Sign extend if necessary.
if (LV.isBitfieldSigned()) {
llvm::Value *ExtraBits = llvm::ConstantInt::get(EltTy,
EltTySize - BitfieldSize);
Val = Builder.CreateAShr(Builder.CreateShl(Val, ExtraBits),
ExtraBits, "bf.val.sext");
}
// The bitfield type and the normal type differ when the storage sizes
// differ (currently just _Bool).
Val = Builder.CreateIntCast(Val, ConvertType(ExprType), false, "tmp");
return RValue::get(Val);
}
// If this is a reference to a subset of the elements of a vector, either
// shuffle the input or extract/insert them as appropriate.
RValue CodeGenFunction::EmitLoadOfExtVectorElementLValue(LValue LV,
QualType ExprType) {
llvm::Value *Vec = Builder.CreateLoad(LV.getExtVectorAddr(),
LV.isVolatileQualified(), "tmp");
const llvm::Constant *Elts = LV.getExtVectorElts();
// If the result of the expression is a non-vector type, we must be
// extracting a single element. Just codegen as an extractelement.
const VectorType *ExprVT = ExprType->getAsVectorType();
if (!ExprVT) {
unsigned InIdx = getAccessedFieldNo(0, Elts);
llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
return RValue::get(Builder.CreateExtractElement(Vec, Elt, "tmp"));
}
// If the source and destination have the same number of elements, use a
// vector shuffle instead of insert/extracts.
unsigned NumResultElts = ExprVT->getNumElements();
unsigned NumSourceElts =
cast<llvm::VectorType>(Vec->getType())->getNumElements();
if (NumResultElts == NumSourceElts) {
llvm::SmallVector<llvm::Constant*, 4> Mask;
for (unsigned i = 0; i != NumResultElts; ++i) {
unsigned InIdx = getAccessedFieldNo(i, Elts);
Mask.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx));
}
llvm::Value *MaskV = llvm::ConstantVector::get(&Mask[0], Mask.size());
Vec = Builder.CreateShuffleVector(Vec,
llvm::UndefValue::get(Vec->getType()),
MaskV, "tmp");
return RValue::get(Vec);
}
// Start out with an undef of the result type.
llvm::Value *Result = llvm::UndefValue::get(ConvertType(ExprType));
// Extract/Insert each element of the result.
for (unsigned i = 0; i != NumResultElts; ++i) {
unsigned InIdx = getAccessedFieldNo(i, Elts);
llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
Elt = Builder.CreateExtractElement(Vec, Elt, "tmp");
llvm::Value *OutIdx = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
Result = Builder.CreateInsertElement(Result, Elt, OutIdx, "tmp");
}
return RValue::get(Result);
}
/// EmitStoreThroughLValue - Store the specified rvalue into the specified
/// lvalue, where both are guaranteed to the have the same type, and that type
/// is 'Ty'.
void CodeGenFunction::EmitStoreThroughLValue(RValue Src, LValue Dst,
QualType Ty) {
if (!Dst.isSimple()) {
if (Dst.isVectorElt()) {
// Read/modify/write the vector, inserting the new element.
llvm::Value *Vec = Builder.CreateLoad(Dst.getVectorAddr(),
Dst.isVolatileQualified(), "tmp");
Vec = Builder.CreateInsertElement(Vec, Src.getScalarVal(),
Dst.getVectorIdx(), "vecins");
Builder.CreateStore(Vec, Dst.getVectorAddr(),Dst.isVolatileQualified());
return;
}
// If this is an update of extended vector elements, insert them as
// appropriate.
if (Dst.isExtVectorElt())
return EmitStoreThroughExtVectorComponentLValue(Src, Dst, Ty);
if (Dst.isBitfield())
return EmitStoreThroughBitfieldLValue(Src, Dst, Ty);
assert(0 && "Unknown LValue type");
}
llvm::Value *DstAddr = Dst.getAddress();
assert(Src.isScalar() && "Can't emit an agg store with this method");
// FIXME: Handle volatility etc.
const llvm::Type *SrcTy = Src.getScalarVal()->getType();
const llvm::PointerType *DstPtr = cast<llvm::PointerType>(DstAddr->getType());
const llvm::Type *AddrTy = DstPtr->getElementType();
unsigned AS = DstPtr->getAddressSpace();
if (AddrTy != SrcTy)
DstAddr = Builder.CreateBitCast(DstAddr,
llvm::PointerType::get(SrcTy, AS),
"storetmp");
Builder.CreateStore(Src.getScalarVal(), DstAddr, Dst.isVolatileQualified());
}
void CodeGenFunction::EmitStoreThroughBitfieldLValue(RValue Src, LValue Dst,
QualType Ty) {
unsigned StartBit = Dst.getBitfieldStartBit();
unsigned BitfieldSize = Dst.getBitfieldSize();
llvm::Value *Ptr = Dst.getBitfieldAddr();
const llvm::Type *EltTy =
cast<llvm::PointerType>(Ptr->getType())->getElementType();
unsigned EltTySize = CGM.getTargetData().getTypeSizeInBits(EltTy);
// Get the new value, cast to the appropriate type and masked to
// exactly the size of the bit-field.
llvm::Value *NewVal = Src.getScalarVal();
NewVal = Builder.CreateIntCast(NewVal, EltTy, false, "tmp");
llvm::Constant *Mask =
llvm::ConstantInt::get(llvm::APInt::getLowBitsSet(EltTySize, BitfieldSize));
NewVal = Builder.CreateAnd(NewVal, Mask, "bf.value");
// In some cases the bitfield may straddle two memory locations.
// Emit the low part first and check to see if the high needs to be
// done.
unsigned LowBits = std::min(BitfieldSize, EltTySize - StartBit);
llvm::Value *LowVal = Builder.CreateLoad(Ptr, Dst.isVolatileQualified(),
"bf.prev.low");
// Compute the mask for zero-ing the low part of this bitfield.
llvm::Constant *InvMask =
llvm::ConstantInt::get(~llvm::APInt::getBitsSet(EltTySize, StartBit,
StartBit + LowBits));
// Compute the new low part as
// LowVal = (LowVal & InvMask) | (NewVal << StartBit),
// with the shift of NewVal implicitly stripping the high bits.
llvm::Value *NewLowVal =
Builder.CreateShl(NewVal, llvm::ConstantInt::get(EltTy, StartBit),
"bf.value.lo");
LowVal = Builder.CreateAnd(LowVal, InvMask, "bf.prev.lo.cleared");
LowVal = Builder.CreateOr(LowVal, NewLowVal, "bf.new.lo");
// Write back.
Builder.CreateStore(LowVal, Ptr, Dst.isVolatileQualified());
// If the low part doesn't cover the bitfield emit a high part.
if (LowBits < BitfieldSize) {
unsigned HighBits = BitfieldSize - LowBits;
llvm::Value *HighPtr =
Builder.CreateGEP(Ptr, llvm::ConstantInt::get(llvm::Type::Int32Ty, 1),
"bf.ptr.hi");
llvm::Value *HighVal = Builder.CreateLoad(HighPtr,
Dst.isVolatileQualified(),
"bf.prev.hi");
// Compute the mask for zero-ing the high part of this bitfield.
llvm::Constant *InvMask =
llvm::ConstantInt::get(~llvm::APInt::getLowBitsSet(EltTySize, HighBits));
// Compute the new high part as
// HighVal = (HighVal & InvMask) | (NewVal lshr LowBits),
// where the high bits of NewVal have already been cleared and the
// shift stripping the low bits.
llvm::Value *NewHighVal =
Builder.CreateLShr(NewVal, llvm::ConstantInt::get(EltTy, LowBits),
"bf.value.high");
HighVal = Builder.CreateAnd(HighVal, InvMask, "bf.prev.hi.cleared");
HighVal = Builder.CreateOr(HighVal, NewHighVal, "bf.new.hi");
// Write back.
Builder.CreateStore(HighVal, HighPtr, Dst.isVolatileQualified());
}
}
void CodeGenFunction::EmitStoreThroughExtVectorComponentLValue(RValue Src,
LValue Dst,
QualType Ty) {
// This access turns into a read/modify/write of the vector. Load the input
// value now.
llvm::Value *Vec = Builder.CreateLoad(Dst.getExtVectorAddr(),
Dst.isVolatileQualified(), "tmp");
const llvm::Constant *Elts = Dst.getExtVectorElts();
llvm::Value *SrcVal = Src.getScalarVal();
if (const VectorType *VTy = Ty->getAsVectorType()) {
unsigned NumSrcElts = VTy->getNumElements();
// Extract/Insert each element.
for (unsigned i = 0; i != NumSrcElts; ++i) {
llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, i);
Elt = Builder.CreateExtractElement(SrcVal, Elt, "tmp");
unsigned Idx = getAccessedFieldNo(i, Elts);
llvm::Value *OutIdx = llvm::ConstantInt::get(llvm::Type::Int32Ty, Idx);
Vec = Builder.CreateInsertElement(Vec, Elt, OutIdx, "tmp");
}
} else {
// If the Src is a scalar (not a vector) it must be updating one element.
unsigned InIdx = getAccessedFieldNo(0, Elts);
llvm::Value *Elt = llvm::ConstantInt::get(llvm::Type::Int32Ty, InIdx);
Vec = Builder.CreateInsertElement(Vec, SrcVal, Elt, "tmp");
}
Builder.CreateStore(Vec, Dst.getExtVectorAddr(), Dst.isVolatileQualified());
}
LValue CodeGenFunction::EmitDeclRefLValue(const DeclRefExpr *E) {
const VarDecl *VD = dyn_cast<VarDecl>(E->getDecl());
if (VD && (VD->isBlockVarDecl() || isa<ParmVarDecl>(VD) ||
isa<ImplicitParamDecl>(VD))) {
if (VD->getStorageClass() == VarDecl::Extern)
return LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
E->getType().getCVRQualifiers());
else {
llvm::Value *V = LocalDeclMap[VD];
assert(V && "BlockVarDecl not entered in LocalDeclMap?");
return LValue::MakeAddr(V, E->getType().getCVRQualifiers());
}
} else if (VD && VD->isFileVarDecl()) {
return LValue::MakeAddr(CGM.GetAddrOfGlobalVar(VD),
E->getType().getCVRQualifiers());
} else if (const FunctionDecl *FD = dyn_cast<FunctionDecl>(E->getDecl())) {
return LValue::MakeAddr(CGM.GetAddrOfFunction(FD),
E->getType().getCVRQualifiers());
}
else if (const ImplicitParamDecl *IPD =
dyn_cast<ImplicitParamDecl>(E->getDecl())) {
llvm::Value *V = LocalDeclMap[IPD];
assert(V && "BlockVarDecl not entered in LocalDeclMap?");
return LValue::MakeAddr(V, E->getType().getCVRQualifiers());
}
assert(0 && "Unimp declref");
//an invalid LValue, but the assert will
//ensure that this point is never reached.
return LValue();
}
LValue CodeGenFunction::EmitUnaryOpLValue(const UnaryOperator *E) {
// __extension__ doesn't affect lvalue-ness.
if (E->getOpcode() == UnaryOperator::Extension)
return EmitLValue(E->getSubExpr());
QualType ExprTy = getContext().getCanonicalType(E->getSubExpr()->getType());
switch (E->getOpcode()) {
default: assert(0 && "Unknown unary operator lvalue!");
case UnaryOperator::Deref:
return LValue::MakeAddr(EmitScalarExpr(E->getSubExpr()),
ExprTy->getAsPointerType()->getPointeeType()
.getCVRQualifiers());
case UnaryOperator::Real:
case UnaryOperator::Imag:
LValue LV = EmitLValue(E->getSubExpr());
unsigned Idx = E->getOpcode() == UnaryOperator::Imag;
return LValue::MakeAddr(Builder.CreateStructGEP(LV.getAddress(),
Idx, "idx"),
ExprTy.getCVRQualifiers());
}
}
LValue CodeGenFunction::EmitStringLiteralLValue(const StringLiteral *E) {
llvm::Constant *C =
CGM.GetAddrOfConstantString(CGM.getStringForStringLiteral(E));
return LValue::MakeAddr(C,0);
}
LValue CodeGenFunction::EmitPredefinedLValue(const PredefinedExpr *E) {
std::string FunctionName;
if(const FunctionDecl *FD = dyn_cast<FunctionDecl>(CurFuncDecl)) {
FunctionName = FD->getName();
}
else {
assert(0 && "Attempting to load predefined constant for invalid decl type");
}
std::string GlobalVarName;
switch (E->getIdentType()) {
default:
assert(0 && "unknown pre-defined ident type");
case PredefinedExpr::Func:
GlobalVarName = "__func__.";
break;
case PredefinedExpr::Function:
GlobalVarName = "__FUNCTION__.";
break;
case PredefinedExpr::PrettyFunction:
// FIXME:: Demangle C++ method names
GlobalVarName = "__PRETTY_FUNCTION__.";
break;
}
GlobalVarName += FunctionName;
// FIXME: Can cache/reuse these within the module.
llvm::Constant *C=llvm::ConstantArray::get(FunctionName);
// Create a global variable for this.
C = new llvm::GlobalVariable(C->getType(), true,
llvm::GlobalValue::InternalLinkage,
C, GlobalVarName, CurFn->getParent());
return LValue::MakeAddr(C,0);
}
LValue CodeGenFunction::EmitArraySubscriptExpr(const ArraySubscriptExpr *E) {
// The index must always be an integer, which is not an aggregate. Emit it.
llvm::Value *Idx = EmitScalarExpr(E->getIdx());
// If the base is a vector type, then we are forming a vector element lvalue
// with this subscript.
if (E->getBase()->getType()->isVectorType()) {
// Emit the vector as an lvalue to get its address.
LValue LHS = EmitLValue(E->getBase());
assert(LHS.isSimple() && "Can only subscript lvalue vectors here!");
// FIXME: This should properly sign/zero/extend or truncate Idx to i32.
return LValue::MakeVectorElt(LHS.getAddress(), Idx,
E->getBase()->getType().getCVRQualifiers());
}
// The base must be a pointer, which is not an aggregate. Emit it.
llvm::Value *Base = EmitScalarExpr(E->getBase());
// Extend or truncate the index type to 32 or 64-bits.
QualType IdxTy = E->getIdx()->getType();
bool IdxSigned = IdxTy->isSignedIntegerType();
unsigned IdxBitwidth = cast<llvm::IntegerType>(Idx->getType())->getBitWidth();
if (IdxBitwidth != LLVMPointerWidth)
Idx = Builder.CreateIntCast(Idx, llvm::IntegerType::get(LLVMPointerWidth),
IdxSigned, "idxprom");
// We know that the pointer points to a type of the correct size, unless the
// size is a VLA.
if (!E->getType()->isConstantSizeType())
assert(0 && "VLA idx not implemented");
QualType ExprTy = getContext().getCanonicalType(E->getBase()->getType());
return LValue::MakeAddr(Builder.CreateGEP(Base, Idx, "arrayidx"),
ExprTy->getAsPointerType()->getPointeeType()
.getCVRQualifiers());
}
static
llvm::Constant *GenerateConstantVector(llvm::SmallVector<unsigned, 4> &Elts) {
llvm::SmallVector<llvm::Constant *, 4> CElts;
for (unsigned i = 0, e = Elts.size(); i != e; ++i)
CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, Elts[i]));
return llvm::ConstantVector::get(&CElts[0], CElts.size());
}
LValue CodeGenFunction::
EmitExtVectorElementExpr(const ExtVectorElementExpr *E) {
// Emit the base vector as an l-value.
LValue Base = EmitLValue(E->getBase());
// Encode the element access list into a vector of unsigned indices.
llvm::SmallVector<unsigned, 4> Indices;
E->getEncodedElementAccess(Indices);
if (Base.isSimple()) {
llvm::Constant *CV = GenerateConstantVector(Indices);
return LValue::MakeExtVectorElt(Base.getAddress(), CV,
E->getBase()->getType().getCVRQualifiers());
}
assert(Base.isExtVectorElt() && "Can only subscript lvalue vec elts here!");
llvm::Constant *BaseElts = Base.getExtVectorElts();
llvm::SmallVector<llvm::Constant *, 4> CElts;
for (unsigned i = 0, e = Indices.size(); i != e; ++i) {
if (isa<llvm::ConstantAggregateZero>(BaseElts))
CElts.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
else
CElts.push_back(BaseElts->getOperand(Indices[i]));
}
llvm::Constant *CV = llvm::ConstantVector::get(&CElts[0], CElts.size());
return LValue::MakeExtVectorElt(Base.getExtVectorAddr(), CV,
E->getBase()->getType().getCVRQualifiers());
}
LValue CodeGenFunction::EmitMemberExpr(const MemberExpr *E) {
bool isUnion = false;
Expr *BaseExpr = E->getBase();
llvm::Value *BaseValue = NULL;
unsigned CVRQualifiers=0;
// If this is s.x, emit s as an lvalue. If it is s->x, emit s as a scalar.
if (E->isArrow()) {
BaseValue = EmitScalarExpr(BaseExpr);
const PointerType *PTy =
cast<PointerType>(getContext().getCanonicalType(BaseExpr->getType()));
if (PTy->getPointeeType()->isUnionType())
isUnion = true;
CVRQualifiers = PTy->getPointeeType().getCVRQualifiers();
}
else {
LValue BaseLV = EmitLValue(BaseExpr);
// FIXME: this isn't right for bitfields.
BaseValue = BaseLV.getAddress();
if (BaseExpr->getType()->isUnionType())
isUnion = true;
CVRQualifiers = BaseExpr->getType().getCVRQualifiers();
}
FieldDecl *Field = E->getMemberDecl();
return EmitLValueForField(BaseValue, Field, isUnion, CVRQualifiers);
}
LValue CodeGenFunction::EmitLValueForField(llvm::Value* BaseValue,
FieldDecl* Field,
bool isUnion,
unsigned CVRQualifiers)
{
llvm::Value *V;
unsigned idx = CGM.getTypes().getLLVMFieldNo(Field);
if (Field->isBitField()) {
// FIXME: CodeGenTypes should expose a method to get the appropriate
// type for FieldTy (the appropriate type is ABI-dependent).
const llvm::Type *FieldTy = CGM.getTypes().ConvertTypeForMem(Field->getType());
const llvm::PointerType *BaseTy =
cast<llvm::PointerType>(BaseValue->getType());
unsigned AS = BaseTy->getAddressSpace();
BaseValue = Builder.CreateBitCast(BaseValue,
llvm::PointerType::get(FieldTy, AS),
"tmp");
V = Builder.CreateGEP(BaseValue,
llvm::ConstantInt::get(llvm::Type::Int32Ty, idx),
"tmp");
CodeGenTypes::BitFieldInfo bitFieldInfo =
CGM.getTypes().getBitFieldInfo(Field);
return LValue::MakeBitfield(V, bitFieldInfo.Begin, bitFieldInfo.Size,
Field->getType()->isSignedIntegerType(),
Field->getType().getCVRQualifiers()|CVRQualifiers);
}
V = Builder.CreateStructGEP(BaseValue, idx, "tmp");
// Match union field type.
if (isUnion) {
const llvm::Type *FieldTy =
CGM.getTypes().ConvertTypeForMem(Field->getType());
const llvm::PointerType * BaseTy =
cast<llvm::PointerType>(BaseValue->getType());
unsigned AS = BaseTy->getAddressSpace();
V = Builder.CreateBitCast(V,
llvm::PointerType::get(FieldTy, AS),
"tmp");
}
return LValue::MakeAddr(V,
Field->getType().getCVRQualifiers()|CVRQualifiers);
}
LValue CodeGenFunction::EmitCompoundLiteralLValue(const CompoundLiteralExpr* E)
{
const llvm::Type *LTy = ConvertType(E->getType());
llvm::Value *DeclPtr = CreateTempAlloca(LTy, ".compoundliteral");
const Expr* InitExpr = E->getInitializer();
LValue Result = LValue::MakeAddr(DeclPtr, E->getType().getCVRQualifiers());
if (E->getType()->isComplexType()) {
EmitComplexExprIntoAddr(InitExpr, DeclPtr, false);
} else if (hasAggregateLLVMType(E->getType())) {
EmitAnyExpr(InitExpr, DeclPtr, false);
} else {
EmitStoreThroughLValue(EmitAnyExpr(InitExpr), Result, E->getType());
}
return Result;
}
//===--------------------------------------------------------------------===//
// Expression Emission
//===--------------------------------------------------------------------===//
RValue CodeGenFunction::EmitCallExpr(const CallExpr *E) {
if (const ImplicitCastExpr *IcExpr =
dyn_cast<const ImplicitCastExpr>(E->getCallee()))
if (const DeclRefExpr *DRExpr =
dyn_cast<const DeclRefExpr>(IcExpr->getSubExpr()))
if (const FunctionDecl *FDecl =
dyn_cast<const FunctionDecl>(DRExpr->getDecl()))
if (unsigned builtinID = FDecl->getIdentifier()->getBuiltinID())
return EmitBuiltinExpr(builtinID, E);
llvm::Value *Callee = EmitScalarExpr(E->getCallee());
return EmitCallExpr(Callee, E->getCallee()->getType(),
E->arg_begin(), E->arg_end());
}
RValue CodeGenFunction::EmitCallExpr(Expr *FnExpr,
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd) {
llvm::Value *Callee = EmitScalarExpr(FnExpr);
return EmitCallExpr(Callee, FnExpr->getType(), ArgBeg, ArgEnd);
}
LValue CodeGenFunction::EmitCallExprLValue(const CallExpr *E) {
// Can only get l-value for call expression returning aggregate type
RValue RV = EmitCallExpr(E);
// FIXME: can this be volatile?
return LValue::MakeAddr(RV.getAggregateAddr(),
E->getType().getCVRQualifiers());
}
LValue CodeGenFunction::EmitObjCIvarRefLValue(const ObjCIvarRefExpr *E) {
// Objective-C objects are traditionally C structures with their layout
// defined at compile-time. In some implementations, their layout is not
// defined until run time in order to allow instance variables to be added to
// a class without recompiling all of the subclasses. If this is the case
// then the CGObjCRuntime subclass must return true to LateBoundIvars and
// implement the lookup itself.
if (CGM.getObjCRuntime()->LateBoundIVars()) {
assert(0 && "FIXME: Implement support for late-bound instance variables");
return LValue(); // Not reached.
}
// Get a structure type for the object
QualType ExprTy = E->getBase()->getType();
const llvm::Type *ObjectType = ConvertType(ExprTy);
// TODO: Add a special case for isa (index 0)
// Work out which index the ivar is
const ObjCIvarDecl *Decl = E->getDecl();
unsigned Index = CGM.getTypes().getLLVMFieldNo(Decl);
// Get object pointer and coerce object pointer to correct type.
llvm::Value *Object = EmitLValue(E->getBase()).getAddress();
// FIXME: Volatility
Object = Builder.CreateLoad(Object, E->getDecl()->getName());
if (Object->getType() != ObjectType)
Object = Builder.CreateBitCast(Object, ObjectType);
// Return a pointer to the right element.
// FIXME: volatile
return LValue::MakeAddr(Builder.CreateStructGEP(Object, Index,
Decl->getName()),0);
}
RValue CodeGenFunction::EmitCallExpr(llvm::Value *Callee, QualType FnType,
CallExpr::const_arg_iterator ArgBeg,
CallExpr::const_arg_iterator ArgEnd) {
// The callee type will always be a pointer to function type, get the function
// type.
FnType = FnType->getAsPointerType()->getPointeeType();
QualType ResultType = FnType->getAsFunctionType()->getResultType();
llvm::SmallVector<llvm::Value*, 16> Args;
// Handle struct-return functions by passing a pointer to the location that
// we would like to return into.
if (hasAggregateLLVMType(ResultType)) {
// Create a temporary alloca to hold the result of the call. :(
Args.push_back(CreateTempAlloca(ConvertType(ResultType)));
// FIXME: set the stret attribute on the argument.
}
for (CallExpr::const_arg_iterator I = ArgBeg; I != ArgEnd; ++I) {
QualType ArgTy = I->getType();
if (!hasAggregateLLVMType(ArgTy)) {
// Scalar argument is passed by-value.
Args.push_back(EmitScalarExpr(*I));
} else if (ArgTy->isAnyComplexType()) {
// Make a temporary alloca to pass the argument.
llvm::Value *DestMem = CreateTempAlloca(ConvertType(ArgTy));
EmitComplexExprIntoAddr(*I, DestMem, false);
Args.push_back(DestMem);
} else {
llvm::Value *DestMem = CreateTempAlloca(ConvertType(ArgTy));
EmitAggExpr(*I, DestMem, false);
Args.push_back(DestMem);
}
}
llvm::CallInst *CI = Builder.CreateCall(Callee,&Args[0],&Args[0]+Args.size());
// Note that there is parallel code in SetFunctionAttributes in CodeGenModule
llvm::SmallVector<llvm::ParamAttrsWithIndex, 8> ParamAttrList;
if (hasAggregateLLVMType(ResultType))
ParamAttrList.push_back(
llvm::ParamAttrsWithIndex::get(1, llvm::ParamAttr::StructRet));
unsigned increment = hasAggregateLLVMType(ResultType) ? 2 : 1;
unsigned i = 0;
for (CallExpr::const_arg_iterator I = ArgBeg; I != ArgEnd; ++I, ++i) {
QualType ParamType = I->getType();
unsigned ParamAttrs = 0;
if (ParamType->isRecordType())
ParamAttrs |= llvm::ParamAttr::ByVal;
if (ParamType->isSignedIntegerType() && ParamType->isPromotableIntegerType())
ParamAttrs |= llvm::ParamAttr::SExt;
if (ParamType->isUnsignedIntegerType() && ParamType->isPromotableIntegerType())
ParamAttrs |= llvm::ParamAttr::ZExt;
if (ParamAttrs)
ParamAttrList.push_back(llvm::ParamAttrsWithIndex::get(i + increment,
ParamAttrs));
}
CI->setParamAttrs(llvm::PAListPtr::get(ParamAttrList.begin(),
ParamAttrList.size()));
if (const llvm::Function *F = dyn_cast<llvm::Function>(Callee))
CI->setCallingConv(F->getCallingConv());
if (CI->getType() != llvm::Type::VoidTy)
CI->setName("call");
else if (ResultType->isAnyComplexType())
return RValue::getComplex(LoadComplexFromAddr(Args[0], false));
else if (hasAggregateLLVMType(ResultType))
// Struct return.
return RValue::getAggregate(Args[0]);
else {
// void return.
assert(ResultType->isVoidType() && "Should only have a void expr here");
CI = 0;
}
return RValue::get(CI);
}
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